Abrading machine



March 30, 1948. "r. G.'cusT|N ET AL 2,438,543

ABRADING MACHINE Filed Jan. 8, 1945 3 sheets-sheet 1 I QAM/MW 2770777575G. [L/52h? Haber? 5. 570175777527 T. G. CUSTIN ET AL March 30, 1948.

ABRADING MACHINE Filed Jan. 8, 1945 5 Sheets-Sheet 2 U@ fm M55. p a @REM@mm W. ,SEEN s H J Ft fc March 30, 1948. T. G. CUSTIN ET Al.

ABRADING MACHINE Filed Jan. 8, 1945 s sheets-sneek 5 atented Mar. 30,1948 ABRADING MACHINE Thomas G. Custin and Robert G. Stoneman,Milwaukee, Wis., assignors of one-third to Jack Shaw, Milwaukee, Wis.

Application January 8, 1945, Serial No. 571,732

15 Claims.

rl`his invention relates to automatic abrading machines and refersparticularly to a skate sharpening machine.

It is a general object of this invention to provide a skate sharpeningmachine so designed and constructed that operation thereof may beautomatic and coin controlled.

Another object of this invention is to provide a machine of thecharacter described s designed and constructed that operation thereofrequires merely proper placing of the skate in a receptacle or holder oflthe machine and proper ac* tuation of the coin controlled startingswitch.

More specifically, it is an object of this invention to provide a skatesharpening machine having means to clamp or grip the skate t0 besharpened and having a grinder or other suitable sharpening tooloperable upon relative motion between the clamp and the tool to properlygrind the edge of the skate blade and wherein the clamping of the skateand the relative motion between the clamp and the tool is eifected by acoin controlled power drive.

A further object of this invention resides in the provision of a novelform of clamp for gripping and holding the skate to be sharpened.

Another object of this invention resides in the provision of a novelmanner of movably mounting the grinder or other sharpening tool fortraversal across the length of the skate blade to be sharpened.

With the above and other objects in View which will appear as thedescription proceeds, this invention resides in the lnovel construction,combination and arrangement of parts substantially as hereinafterdescribed, and more particularly' dened by the appended claims, it beingunderstood that such changes in the precise embodiment of thehereindisclosed invention may be made as come Within the scope of theclaims.

The accompanying drawings illustrate one complete example of thephysical embodiment of the invention constructed in accordance with thebest mode so far devised for the practical application of the principlesthereof, and in Which- Figure 1 is a perspective view illustrating theexterior of the upper portion of a machine constructed in accordancewith this invention;

Figure 2 is a top plan view of the machine with the cover of the cabinetremoved and with parts broken away and in section;

Figure 3 is a detail sectional view taken through Figure 2 on the planeof the line 3 3;

Figure 4 is a view partly in end elevation and partly in section;

Figure 5 is a detail sectional view taken through Figure 3 on the planeof the line 5 5;

Figure 6 is a diagrammatic View to illustrate the manner in which thetilt of the tool carrying carriage is limited;

Figure 7 is a diagrammatic view illustrating the manner in which thecoin mechanism controls operation of the machine; and

Figure 8 is a view illustrating a slightly varied form of grinding wheelwhich may be used to facilitate grinding the ends of the skates.

Before specically defining the illustrated embodiment of the invention,the general aspects of the machine will be outlined.

The machine is preferably housed within a neat cabinet so as to beunobtrusive when installed at public and private rinks. of the cabinetis an opening which constitutes a receptacle for the skate to besharpened. The skate is placed in this opening with its blade downwardlyso as to engage between the jaws of a clamp which grip the blade andsecurely hold the same the instant the machine is started. Starting ofthe machine is effected by means of a coin controlled switch.

.A carriage arranged to move back and forth and driven by a reversibleelectric motor started by the coin controlled switch mechanism drivesthe grinder and propels the carriage from one end of the machine to theother and back again to cause the grinder to traverse the length of theskate blade twice.

When the carriage carrying the grinder returns to its normal initialposition the clamp is automatically opened and the skate is released forremoval, The machine thus operates cyclically with each cycle initiatedby actuation of the coin mechanism.

The machine illustrated has provision for sharpening only one skate at atime but as will be readily apparent from the description to follow, themachine may be easily designed to sharpen two or more skates at onetime.

Referring now particularly to the accompanying drawings in which likenumerals indicate like parts, the numeral 5 designates the cabinet orhousing of the IInachine, the front wall of which carries` aconventional coin mechanism 6, proper actuation of which initiates onecycle of operation of the machine.

'I'he cover of the cabinet has a hole I therein into which the blade ofa skate S may be i11-A At the D013' end as at l2 to the cross member IB.Their opposite free ends are held down on the cross member Il by guidesi4 and tension springs I5 yieldigly draw the rails together, The springsl5 are individually anchored to the'cross member Il, so as to hold therails symmetrically disposed with relation to their bisecting centerline.

The clamp jaws 8 are pivotally connected to the rails i3 by studs I6.The lower ends of these studs also mount rollers l1 for a purpose laterYto be described.

In view of the pivotal connection betweenthe jaws and the rails, therails may move angularly while the faces of the jaws remain parallel toeach other. It is preferable, however, to p rovide light springs I3between the opposite ends of the jaws and their carrying rails to holdthe same substantially parallel as the carrying rails are spread apartand brought together.

As will be readily apparent, the location of the clamp near the pivotedends of the carrying rails gives the clamp considerable leverage so thatthe springs l5 exert a strong clamping force tending to close the clamp.

A skate gripped by the clamp is in position to be acted upon by agrinder or other appropriate sharpening tool i9 as the latter is movedback and forth along the length of the machine. This grinder orsharpening tool is mounted on a carriage 20 by means of an arbor 2|journalled in a bearing structure 22 depending from the undersurface ofthe carriage The carriage is slidably supported on a shaft 23 extendingbetween the cross members I0 and Il. v

In addition to the grinder, the carriage carries a reversible electricmotor 24. It is to be observed that the motor is at one side of thepivotal sliding carriage support provided by the shaft 23 and that thegrinder is at the opposite side of this fulcrum. The weight of the motorbeing greater than that of the grinder thus biases the grinder upwardlytoward the undersurface or bottom of a skate blade in position in theclamp. A leaf spring 25 secured to the undersurface of the carriage andhaving its free end slidably bearing on a longitudinal supporting rail21 assists in holding the grinder up against the blade of the skateY toguard against chattering and insure smooth operation of the machine. Abelt 28 trained over pulleys on the motor shaft and the grinder arbordrives the grinder directlyfrom the motor.4

In the loading position of the machine thevcarthe clamp jaws to `supporta skate blade and properly locate the same with relation to the `jaws. Y

The end of the bottom guide 39 nearest the grinder has an inclined guide3l fixed thereto, the upper end of which is substantially in line withthe periphery of the grinder so that upon movement of the carriage tobring the grinder under the skate blade the carriage will be depressedby the guide 3| riding under the end of the blade to enable the grinderwheelto be engaged with the blade.

AsY the grinder wheel has a at peripheral surface parallel with itsaxis, the guide 3l must not project beyond the periphery of the wheel..Preferably, it terminates just below the periphery of the wheel riding,but if a grinder wheel having a cross-sectional shape such as shown inFigure 8 is employed the guide 3l need not be so high. Moreover, thegrinder shown in Figure 8 will enable the rounded Yend of the skateblade to be ground as the wheel rides under the blade.

A guide 32 similar to the guide 3l is mounted on the carriage at theopposite side or face of the grinder to function in the manner describedduring the return stroke of the carriage.

Any suitable means may be employed to cause the carriage to traverse thelength of themaehine, but in view of the fact that the carriage must befree to rock about its supporting'shaft 23, a cable drive has been founddesirable. This and worm wheel drive 3E. Hence, when the mo-` torrevolves in one direction the cable is wound one way on the shaft or ona drum carried lthereby to pull the carriage from its normal loadingposition (shown in full lines in Figure 2)*to the opposite end-of theVmachine (shown in dotted Y lines in Figure 2).

riage is at one end of the machine with the grinder spaced beyond theend of a skate in the clamp, and as noted hereinbefore, in thisloading'position of the machine the clamp jaws are held open to permitthe insertion or removal of a skate.

This latter function is performed by two cams 29 1 top surface of thecarriage is in position under During this forward stroke of the carnagethe grinder traverses the lengthV of the skate blade once Vand as willbe readily apparent, during the initial forward motion of the carriagethe cams 29 move from between the rollers il so that the clamping jawscome together to grip the skate and hold the same firmly during thegrinding action.A

When the carriage reaches its dotted line position shown in Figure 2 alreversing switch operates and causes the motor to reverse its directionof rotation.V Thisreturns the carriage toits normal position of rest inthe same manner as described so that the grinder traverses the blade ofthe skate for the second time and as the carriage iinishes its returnstroke the cams 29 ride between the rollers l1 and open 'the clamp torelease the skate.

As noted hereinbefore, the weight of the motor 2d` and the tension ofthe leaf `spring 25 cornbine to urge the front end of the carriagecarrying the grinder upwardly to apply the grinder to the skate with theproper degree of pressure.

The bias imposed upon the carriage in this manner is limited by theengagement of aprojection 31- extended from the rear of the carriage andengageable with a track 3B xedto the rear wall of the cabinet or a`suitable portion of the 4 supporting frame. The position of the carriagedened by the engagement of the projection 31 with the supporting rail 38is illustrated in Figure 6.

In this position the grinder is held below the level of the clamp jawsso that operation of the machine without a skate in place will notresult in grinding of the clamp.

While the specic coin controlled mechanism forms no part of thisinvention and may be of any desired construction capable of performingthe required functions, for purposes of illustration the usual coinmechanism indicated generally by the numeral 39 has been shown providedwith a pusher 4t projected from the rear thereof and operable when aproper coin is used to simultaneously open a normally closed switch iland rock a pivoted lever 42 to actuate a reversing switch e3 to aforward position. This leaves the motor circuit open. Its closurerequires the coin mechanism to be retracted whereupon the motor operatesin the direction to cause the carriage to execute its forward stroke.

At the completion of the forward stroke of the carriage the reversingswitch 43 is actuated as by the engagement of an actuator 44 .with astop l5 to cause the motor to run in the opposite di,- rection andreturn the carriage to its normal position of rest.

During the final return travel of the carriage the reversing switch 43is opened by engagement of the actuator M with another Xed stop 46 andin addition a switch 47 is opened, 'Il-his latter switch is in parallelwith the switch el and is biased to closed position so as to close theinstant the carriage starts its forward stroke.

By requiring the coin controlled mechanism to be retracted to close themotor circuit, assurance is obtained against defeating the coin controlfeature by holding its handle in.

From the foregoing description taken in connection with the accompanyingdrawings, it will be readily apparent that this invention provides apractical wholly automatic skate sharpening machine, which, by virtue ofits capability of coin controlled operation, is exceptionally wellsuited for installation at public and private skating rinks.

What we claim as our invention is:

l. A skate sharpening machine comprising: clamp mechanism adapted togrip a skate; a grinder; means mounting the grinder for back and forthmotion between dened limits along a path so related to the clampmechanism that the grinder traverses the bottom of the blade of a skatein the clamp mechanism; means for driving the grinder back and forthalong said path; and clamp releasing means connected with said grinderso as t0 travel in said back and forth path of travel of the grinder tobe engaged with portions of the clamp mechanism upon motion of thegrinder t0 one of its limits for effecting opening of the clampmechanism and release of the skate.

2. In a skate sharpening machine: a sharpening unit including a carriagemounted :for linear movement between defined limits and a grindercarried by and movable with said carriage; means for moving saidcarriage from and back to a normal position of rest; a skate clamplocated betwten said limits of linear motion of the carriage and adaptedto grip a skate and hold the blade thereof in position to be acted uponby the grinder as it is moved from and back to said position of rest;and cooperating clamp 6 controlling means on the carriage and clampoperable to effect opening of the clamp at the completion of the skatesharpening motion of the sharpening unit and to hold the clamp openwhile the unit is at said normal position of rest.

3. A skate sharpening machine, comprising: a cabinet having an aperturein one wall thereof skate clamp mechanism adjacent to the aperture insaid wall and adapted to hold a skate with its blade projecting throughthe aperture and with its edge to be sharpened exposed at the interiorof the cabinet; grinder mechanism in the cabinet adapted to sharpen theblade upon relative motion between said mechanisms in a directionlengthwise of the blade of a skate in said clamp mechanism; means fixedwith respect to the cabinet mounting one of said mechanisms forreciprocatory motion lengthwise of the skate blade between dened limits;means iixed with respect to the cabinet mounting the other of saidmechanisms in a position alongside the path of movement of saidreciprocatory mechanism and between said limits of motion thereof; apower drive for the machine for reciprocating said reciprocatorymechanism; and control instrumentalities for starting. and stopping saidpower drive including means actuated by the reciprocatory mechanism uponmovement thereof to one of its limits of motion for automaticallyrendering the power drive inoperative.

4. A skate sharpening machine, comprising: a sharpening tool; clampmechanism adapted to grip a skate to be sharpened with its blade exposedfor contact with the sharpening tool; means mounting the sharpening tooland clamp mechanism adjacent to one another and for relative motionlengthwise of the blade of a skate held in the clamp mechanism; a powerdrive for the machine operable to effect said relative motion of thetool and the'clamp mechanism; means for controlling the drive to causecyclical functioning of the machine with relative motion between thetool and the clamp mechanism occurring from and back to a predeterminedinitial loading postion, during which motion forward and retrogradetraversal of the tool and the skate blade occurs for at least the lengthof the skate blade; and cooperating means on the clamp mechanism and thesharpening tool operatively engaged by said relative lengthwise motionof the tool and the clamp mechanism for effecting automatic closure ofthe clamp mechanism at the start of the cycle and opening of the clampmechanism at the end of the cycle so that application and removal of theskate may be elrected only when the parts are in said predeterminedloading position.

5. A skate sharpening machine, comprising the combination of: asharpening unit including a rotatable sharpening tool; clamp mechanismadapted to grip a skate to be sharpened with its blade exposed forcontact with the tool; means mounting the sharpening unit and the clampmechanism adjacent to one another and for relative movement lengthwiseof the blade of a skate held in the clamp mechanism; a power drive forthe machine operable to actuate the sharpening tool and effect saidrelative motion of the sharpening unit and clamp mechanism; means forcontrolling the power drive to cause cyclical functioning thereofwith'relative motion between the sharpening unit and clamp mechanismoccurring from and back to a predetermined loading position of thesharpening unit and clamp mechanism during which motion forward; andretrograde traversal: ofthe sharpening` unit. and the skate occurs. at:least: for the length ofthe skate blade; and cooperating means on theclamp mechanismv and the sharpening unit engaged by relative skatetraversingmotion of the sharpening unit and' the clamp.. mechanism tosaid?y predetermined loading' position offV the parts for effecting,opening of the clamp: mechanism to. release a skate therein at the endof the cycle.

6'. A skate sharpening machine comprisingthe combination. of: asharpening element; a clamp element adapted to grip a skate to-besharpened withl its blade exposed for Contact with the sharpeningelement; means. m-ounting said elements for motion relative tooneanother length-4 wise of the` blade of a skate in the clamp element froma loading position at which the sharpening element is spaced far enoughto one end of the'` clamp element to enable application of" a sk ate tothe clamp, element without contacting the sharpening element, toaposition withthe sharpeningv element at the opposite end of theJclamp.element .reached by. relative traversal of' one of said elementsby theother'and back tosaid'loading position, said: mounting means alsoypermitting said elements to ,be relatively movable towardand from oneanother in a direction trans-l verse to relative lengthwiseA .motiontherebetween; means yi'eldinglybiasing one of'said element-fs toward theother whereby the sharpening element is. yieldinglyv urgedV against theblade of a skate Yinsaid clamp. element under pressure during Yrelative.lengthwise motion between said elements; a power driveV for the machineoperable t-oeiectV said relative lengthwise motion of said elements;meansforfstarting the-power drive and controlling it. to cause thermachine to perform one cycle during; which forward'and Yretrogradetraversal ofthe sharpening element and the skate blade in. the clampelement occurs for the length. of the skate blade; and.,mear 1s for.automatically opening the clampA element. at:l the completion ofV the-`cycle when the elements reltur-n to said loading. position.

combination ofi: a: sharpening tool;Y means: mounting the tool forreciprocating movement betweenv dened limits ar 'clampad'aptedl to gripa skate to bel sharpened with its blade exposed for contact with thesharpening tool? as itzrecip.- rocates between said limits, said tooland' clamp. being mounted for; relatitev motionA toward and from oneanother in a direction. crosswise, to

Yreciprocating movement o' the tool; a power drive for impartingreciprocatory motion to they sharpening tool to cause it to trave-rsethe length of the blade of a skate in; theolamp; means vfor controllingthe power drive. to.` cause; it; to operate in cycles during whichthesharpening: tool is moved; between its; limit-s; of motion at leastonce;`A yieldable, means tending; to: ati all; timeSf '1. A1 skatesharpening.A machinecomprising the eiect relative motion between thesharpening Y tool andthe clamp ofv said transverse-'direction toward,one another wherebythe blade; and tool are maintained in engagementunder p -resslire during; motion; of" the, tool between Vsaid limits.Y

of reciprocatory motion, thereof; and means; on:

me toolV adapted for initial eng-agement, witntne 8; In a machineof'thecharacter described', the combination ofi: a rotatable grindingwheel; means. mounting the. wheel forv bodily reciproca,- tory movementbetween dened limits andi for" rotation. on an axis: parallel to the,path of` bodily motion of the wheel; a pair of levers adjacent to the,path of reciprocatory movement ofthe wheel and extending in theAdirection oiV the axis of rotation. off the wheel; pivotal supports forone end of the levers mountingthe same: for pivotal motion on Xed axesparallelA to one; another and normal to the axis of rotation -o-f thewheel;` means yieldingly urging` the free ends. ofthe levers together;work engaging clamps carried by the leversy near their; pivoted ends andbetween the limitsY of reciprocatory motion of' the; wheel, Said clampsbeing adapted to grip w-ork` and se,- curely hold the same in positionto be acted: upon by the grinding wheelduring reciprocatory movementthereof' between its limits of, motion;` a power drive for the machineoperable to rotate.

the grinding Wheel and to` reciprocate the same Y bodily along saidpath]` of movement thereof; and means for controlling the power drive toinitiate reciprocatory motion of the wheel and tor stop: reciprocatorymotionVV thereof at one. limit of motion of the wheelsothat themachineoperates cyclically.y

9. A skate sharpening machine comprising theLk combinationV of; asharpening tool;V a carriage on which thesharpening toolis mounted;means:

movably supporting'V the'carriage and constraining the same and thesharpening tool there-on; to

reciprocatory motion; a clamp positioned alongside the path ofrecprocatorymotion of the tool,r and adapted tofgr-ip askate-to besharpened and to hold the same with its, blade exposed Yto thesharpening tool as the same reciprocates, said clamp and the carriagebeing relatively movable toward and from eachl other in a: direction.transverse to reciprocatory-,motion of the tool; yieldable means tendingto-at all times effect relative movement between the tool and clamp in:said transverse direc-tion toward one another so that` the blade of a;skate inthe clamp is yieldingly engaged by: thel tool as; the tool'traverses the, length of the blade during reciprocatory motionof thecarriage; a power drive for imparting moti-on to the carriage;` andmeansfor rendering saidpower drivefoperative to eiect reciprocatory Ymotion of the carriage between defined. limits to, carry the tool alongand beyond the blade of a skate; in the clamp and for rendering; saidpower drive ineffective at one of the limits of reciprocatory movementof the, tool. l

1G; A. skate sharpening. machine; comprising the combination of.:l aAsharpening tool); a carriage on which the sharpening tool is mountedadapted to reciprocate between defined limits; means movab'ly.Vsupporting the carriage and constraining the same and the sharpeningtool.

thereon to Vreciprooatory motion between-said predetermined limits;l aclamp positionedv alongside the path of movement ofY the tool andadapted tog-rip a skate to .be sharpened Yand to hold the same with itsbladej extending lengthwise of the path off motion of the carri-age andexposed to thesharpening tool as the same travelsv with theicarriage,said clamp:and:` carriage being rclativelymovabletoward` from.eachotherV ina direction transverse to reciprocatory motion'` ol`= thetool; yieldable means tending to at all: Y

times eilect relative. motion between the clam-pV and' tool-insaidftransverse direction toward= eaclr other sc thatzthe tool; isengaged withthe,blade.

of a skate in the clamp under yielding pressure as the tool traversesthe length of the blade; means for reciprocating the carriage to causethe tool to traverse the length of a skate blade in the clamp includinga power drive and means for controlling said power drive so as to effectreciprocatory motion or the carriage between said dened limits andconsequently traversal of the skate blade by the sharpening tool and forrendering said power drive ineffective at one of the limits ofreciprocatory movement of the tool; and means operated by the carriagefor automatically effecting opening of the clamp as the sharpening toolcomes to rest at said last named limit thus to release the sharpenedskate for removal.

1l. In a skate sharpening device of the character described: a springpowered clamp adapted to grip the blade of a skate; a sharpening toolmovable in opposite directions between predetermined limits to traversethe length of a blade of a skate in the clamp during motion of the tooland thereby effect sharpening of the blade; means for moving thesharpening tool forward and backward across the length of a skate bladein the clamp; and means movable with the sharpening tool along said pathof motion thereof for controlling the operativeness of the clamp7 saidclamp control means actuating the clamp to open the same in consequenceto backward motion of the tool to one of its limits of motion andeffecting closure of the clamp in consequence to initial forward travelof the tool from said designated limit of motion.

12. In a skate sharpening machine of the char-- acter described: a clampadapted to grip the blade of a skate and hold it in a iXed position; asharpening tool; means mounting the sharpening tool for motionlongitudinally of the blade of a skate in the clamp between definedlimits spaced from opposite ends of the skate blade to enable the toolto traverse the length of said blade; means for yieldingly urging thesharpening tool toward the skate blade bottom and to a position beyondthe plane of the blade bottom as the tool leaves the blade during traveltoward either of its limits of motion; and means for guiding thesharpening tool into proper engagement with the blade of a skate in theclamp as the tool travels between its limits of motion.

13. An abrading machine for grinding an edge of a piece of work,comprising: clamping means for releasably securing the work with theedge thereof to be ground exposed; a grinding head including a grindingwheel and means for rotating the same; means pivotally mounting saidgrinding head with the pivotal axis thereof substantially parallel tothe edge to be ground and spaced from the grinding wheel, said mountingmeans enabling the head, by its pivotal motion, to swing the peripheryof said grinding wheel toward and from grinding engagement with saidedge to be ground; means for sliding the head along its pivot axis;means yieldingly biasing said grinding head about its pivotal axis in adirection to urge the grinding wheel into grinding engagement with theedge to be ground and beyond the same; means for effecting cyclicalreciprocatory motion of said grinding head between dened limits so as tocause the grinding wheel to grind said edge along substantially theentire exposed length thereof; and cam means on said grinding headadjacent to said grinding wheel, on either side thereof, cooperable withsaid edge to be ground to cam the grinding wheel into smooth engagementwith said edge as the grinding wheel approaches said exposed edge duringcyclical movement of the grinding head.

14. The machine set forth in claim 13 further characterised by theprovision of cooperating cam means on the clamping means and thegrinding head for effecting closure of the clamping means upon slidingmotion of the head away from one of its limits of motion and foreffecting opening of the clamping means upon sliding motion of thegrinding head to said limit of motion.

A skate sharpening machine comprising: a cabinet having a top wallprovided with an aperture therein through which the blade of a skate maybe passed to have its underside exposed on the interior of the cabinet;clamping means on the cabinet adjacent to said aperture securelygripping the blade of a skate ins ted into said aperture with its bladedownward; a sharpening tool; means inside the cabinet, including areciprocable carriage, mounting sharpening tool for lengthwise traversalof the skate blade between predetermined limits along a path beneathsaid aperture and clamp ing means, said carriage being tiltable about anaxis parallel to reciprocal motion of the carriage to enable thesharpening tool to move toward and from the underside of the blade of ain said clamp; yieldable means biasing the carrriage upwardly so as tomaintain the sharpening tool engaged with the underside of a skate bladeunder pressure; power means for driving said carriage; and control meansfor said power drive for effecting controlled reciprocation of said carnriage to cause the same to traverse the skate blade with a motionstarting from a skate loading position of rest at one end of the bladeof a skate in said clamp to a position at the other end of said blade,and back to said irst named posi.- tion of rest.

THOMAS G. CUSTIN. ROBERT G. STONENIAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,435,387 Goerke Nov. 14, 19221,480,422 Strom Jan. 8, 1924 1,929,810 Edwards et al Oct. 10, 19331,966,869 Owen July 17, 1934 1,967,964 Miller July 24, 1984 2,055,665Moon Sept. 29, 1936 2,358,880 Robinson Sept. 26, 1944

